All photos should have an aspect ratio of 4:3 and be a minimum width of 200 pixels. The aspect ratio is the ratio of the width to the height of an image. You can crop the image to a 4:3 ratio after uploading it but this will not guarantee that you get all the information in an image if you are using an advertisement or brochure from the event.
The calendar will not resize your image. For more information, please refer to Localist FAQ.